P0513 on 2015-2020 GMC Yukon XL: Incorrect Immobilizer Key Causes & Fixes

What's Unique About the 2015-2020 Gmc YUKON XL

For the 2015-2020 GMC Yukon XL (K2XX platform), the P0513 code is frequently linked to underlying electrical issues rather than just a bad key. General Motors has issued several Technical Service Bulletins (TSBs) pointing to specific weak points. These include a poor ground connection at location G218 behind the dash and corroded wiring harnesses under the driver's side sill plate. TSB PIT5391F specifically calls out circuit 5199 as a potential point of failure in the sill plate harness. This circuit provides ignition voltage to the KR73 Ignition Run Relay in the underhood fuse block (UBEC). These issues are common across the entire K2XX platform, affecting the Chevrolet Tahoe, Suburban, Silverado, and Cadillac Escalade as well.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Engine will not start (cranks but won't fire, or no crank at all).
• Engine starts and immediately stalls.
• Security or anti-theft light illuminated or flashing on the dashboard.
• Check Engine Light is on.
• Key fob functions (lock/unlock) may not work.
• In some cases, the Service Engine Soon light may fail to illuminate when it should, as noted in TSB #PIT5391F.
• A "Service Theft Deterrent System" message may appear on the Driver Information Cen 🎬 Watch: How to reset the anti-theft system on GM trucks.ter (DIC).

Most Likely Causes

1. Weak or Dead Key Fob Battery 🔴 High Probability
   How to confirm: Try starting the vehicle with your spare key fob. If it starts, the issue is with the first key. If the fob battery is dead, you can often still start the vehicle by placing the fob in the transmitter pocket, which is located in the center console storage area for these models.
   Typical fix: Replace the battery in the key fob (typically a CR2032). 🎬 Watch: Step-by-step guide to replacing your Yukon key fob battery.
   Est. part cost: $1-$5
2. Poor Body Control Module (BCM) Ground at G218 🟡 Medium Probability A known issue documented by GM in TSB #PIT5405C and its successors. The dash insulator mat can get trapped under the ground eyelet during assembly, causing a poor connection.
   How to confirm: Inspect the G218 ground location, found under the driver's side dashboard near the A-pillar or just under the dash speaker. Check for a loose 10mm nut or the black insulator mat pinched under the ground terminal. The presence of multiple communication (U-prefix) codes along with P0513 strongly points to this issue.
   Typical fix: Remove the nut and ground eyelet, cut away the interfering insulator mat, clean the contact surfaces to bare metal, and securely retighten the ground nut. 🎬 See how to properly clean and fix the G218 ground connection.
   Est. part cost: $0
3. Damaged or Corroded Wiring in Driver's Sill Plate 🟡 Medium Probability Documented in TSB #PIT5391F. Water intrusion into the cabin can cause corrosion in the wiring harnesses that run along the driver's side floor. This area is susceptible to moisture and salt carried in by the driver's feet.
   How to confirm: Remove the driver's side sill plate and peel back the carpet to inspect the wiring harnesses for signs of moisture, corrosion (green or white powder), or physical damage. Pay special attention to circuit 5199, as called out in the TSB. This circuit is critical for the Ignition Run Relay.
   Typical fix: Repair or replace the damaged sections of the wiring harness using waterproof butt connectors or solder and heat shrink tubing. Address the source of any water leak.
   Est. part cost: $10-$100 (for wiring repair supplies)
4. Faulty Key Fob ⚪ Low Probability
   How to confirm: If a new battery and the spare key don't solve the problem, the transponder chip in the key itself may have failed. This requires a professional tool to test.
   Typical fix: Replace and program a new key fob. This must be done by a dealer or an automotive locksmith with the proper equipment.
   Est. part cost: $75-$300

Rare But Worth Checking

• Faulty Immobilizer Antenna Ring: The antenna ring around the ignition switch (or push-start button) reads the key's signal. A failure here is uncommon but can cause P0513 by preventing the signal from being received. A professional scan tool can test the antenna signal strength, which should typically be between -30dBm and -50dBm.
• Body Control Module (BCM) or Engine Control Module (ECM) Failure: In rare cases, the module responsible for the security handshake can fail. This is often a last resort after all other possibilities, especially wiring and grounds, have been eliminated. TSB #21-NA-277 notes that low voltage events can corrupt BCM memory, causing this code. GM explicitly warns technicians *not* to immediately replace modules in this case, as a special procedure may be required.

Diagnosis Steps

1. Try to start the vehicle with a known-good spare key. If it works, the problem is with the primary key.
2. If the spare key doesn't work, replace the battery (CR2032) in the primary key fob. If the battery is dead, try placing the fob in the transmitter pocket in the center console to start the vehicle.
3. Scan the vehicle for all DTCs. Note any other codes, especially communication (U-codes) or BCM/ECM codes, as they can provide crucial clues.
4. If codes listed in TSB #PIT5405C are present, inspect the G218 ground connection behind the driver's side dash for looseness, corrosion, or a trapped insulator mat.
5. If codes from TSB #PIT5391F are present, remove the driver's side sill plate and inspect the wiring harness for any signs of corrosion, water damage, or chafing, paying close attention to circuit 5199.
6. Test the main vehicle battery. Low system voltage can cause communication glitches and trigger a false P0513, as noted in TSB #21-NA-277.
7. If no wiring or ground faults are found, have a qualified technician test the immobilizer antenna ring.
8. If all hardware and wiring checks pass, the issue may be with the BCM or key programming, which requires professional diagnostic equipment.

Parts You'll Likely Need

• Key Fob Battery (OEM #CR2032) — This is the most common and cheapest potential fix. A weak battery can fail to transmit the security code.
  Trusted brands: Energizer, Duracell, Panasonic
  OEM price range: $5-$10
  Aftermarket price range: $1-$5
• Key Fob / Transmitter (6-Button) (OEM #13580804, 13508280 (FCC ID: HYQ1AA)) — If the internal transponder chip is damaged, the entire key fob must be replaced and programmed to the vehicle.
  Trusted brands: ACDelco (OEM), Strattec
  OEM price range: $150-$300
  Aftermarket price range: $75-$150

Related Codes That Often Appear With This One

• P262B — Often cited with P0513 in TSB #PIT5391F, suggesting a common electrical fault related to control module power or the sill plate wiring.
• U0073, U0100, U0101, U0121, U0140 — These communication (U-prefix) codes are listed alongside P0513 in TSB #PIT5405C and strongly point towards a systemic electrical issue, such as the G218 ground fault, disrupting the vehicle's network.

Technical Service Bulletins (TSBs) & Recalls

• PIT5391F: Addresses P0513 with potential wiring damage in the driver sill plate, specifically circuit 5199.
• PIT5405C: Links P0513 to a bad ground at the G218 location due to a trapped insulator mat.
• 18-NA-161: Supersedes PIT5405C, reiterating the G218 ground issue as a cause for P0513 and many other electrical faults.
• 21-NA-277: Warns against module replacement for P0513 after a low-voltage event, indicating a special procedure is needed.

Platform-Specific Known Issues

• TSB #PIT5405C: A poor ground connection at G218, potentially caused by a trapped dash insulator mat, can cause P0513 along with numerous other communication codes. The fix is to cut away the mat and clean the ground.
• TSB #PIT5391F: Damaged or corroded wiring in the driver's sill plate area, specifically circuit 5199, can lead to P0513 and other electrical issues, including a no-crank or start-and-stall condition.
• TSB #21-NA-277 & #23-NA-165: Low voltage events (like a jump start or battery replacement) can corrupt the BCM's memory, leading to P0513 and a no-start condition. GM advises against immediately replacing modules or performing immobilizer relearns in this case, as a special procedure may be needed.

Scan Tool Commands That Help

• GDS2 (GM Dealer Scan Tool): Immobilizer Learn — Used for programming new keys or relearning existing keys after a component replacement (BCM, ECM, etc.). This function erases all previously learned keys and requires all keys to be present for the procedure.
• GDS2 (GM Dealer Scan Tool): BCM Programming (via SPS) — Required when installing a new Body Control Module to load the correct software and vehicle configuration. A special VCI (Vehicle Configuration Index) may be needed from GM's Technical Assistance Center (TAC) in cases of BCM memory corruption from low voltage, as per TSB 21-NA-277.
• GDS2 (GM Dealer Scan Tool): Module Self-Test — Can be used to command the BCM to perform an internal self-check. A failure indicates internal module corruption that may not be fixable by wiring repairs or reprogramming.

Wiring & Ground Locations

• G218 — Under the driver's side of the instrument panel, near the A-pillar kick panel, often just below the dash speaker.. This is a primary ground point for the Body Control Module (BCM). As documented in TSB PIT5405C, the dash insulator mat can get trapped under the ground's eyelet, causing high resistance and leading to P0513 and multiple communication codes.
• Circuit 5199 — Runs in the wiring harness located under the driver's side sill plate. It connects the BCM to the Underhood Fuse Block (UBEC).. This circuit provides the signal to energize the KR73 Ignition Run Relay. TSB PIT5391F identifies that corrosion or an open in this wire prevents the relay from turning on, causing a no-start or start-and-stall condition, which sets P0513.
• X50A (Underhood Fuse Block) — The main fuse and relay center in the engine bay.. TSB PIT5391F points to potential poor terminal fit at connector X4, pin M5 for circuit 5199 within this fuse block. A bad connection here has the same effect as a corroded wire in the sill plate.
• X51L (Left I/P Fuse Block) — Fuse block located inside the cabin, on the driver's side of the dashboard.. TSB PIT5391F also notes to inspect for poor terminal connections at this fuse block, specifically at connector X1, pin 42 for circuit 5199.
• G103 — Located at the left rear of the engine compartment on the cowl, above the brake booster.. This is another ground point for the BCM, Instrument Panel Cluster (IPC), and Data Link Connector (DLC). While G218 is the most cited culprit, a fault at G103 could also cause similar communication and module power issues.

Real Owner Repair Stories

• YouTube user comment on 'G218 Ground Issue Fix' video (2014-2018 Chevrolet Silverado/GMC Sierra (K2XX Platform)) — Unspecified electrical issues leading to a 'major headache'.
  ❌ Tried (didn't work) Hours of online research trying to diagnose the ground issue.
  ✅ What actually fixed it Following the video's instructions to access the G218 ground under the driver's side dash, move the interfering foam insulation away from the ground nut, and ensure the connection was tight. The entire fix took the owner 30 minutes.

OEM Part Supersession History

• 13587704, 13594764, and others → Varies by VIN, latest part number must be used. — Standard part revisions and consolidation by the manufacturer.
  Heads up: A replacement BCM must be programmed using GM's Service Programming System (SPS) to function. Simply swapping the part will result in a no-start condition. Some vendors offer a cloning service where they transfer data from the old BCM to the new one, avoiding the need for dealer programming.